Prior treatments of presbyopia include bifocal spectacles, progressive addition lenses, and multifocal contact lenses, as well as reading glasses. The prior approaches can have the disadvantage of not providing focusing power that is dynamic and controllable by the user.
Although it has been proposed to provide a dynamic change in focus, these prior approaches can be less than ideal in at least some instances. It has been proposed to provide a dynamic change in focusing power of the optic using electric voltage to provide the energy and electronic sensing to monitor physiological trigger responses, for example, electronic eye glasses and intraocular lenses comprising a dynamic add power. However, such electronic approaches can be more complex than would be ideal. Electronic control of the optical properties of the lens optic and sensing of the physiological trigger can add substantial complexity to the design and manufacturing process of such products in at least some instances.
Multifocal contact lenses have been proposed with at least two or more optical zones of different focal lengths, and such lenses are less than ideal in at least some instances. Vision correction can be provided by multifocal contact lenses that have optical zones of different focusing power disposed radially symmetrically about the optical center of the lens. However, such multifocal contact lenses can degrade vision, as the light from the portions of the lens having both focal lengths may not both be in focus. Far objects can be in focus with the part of the lens for far vision, and yet also blurred with the part of the lens for near vision. While near vision may improve with such lenses with the part of the lens for near vision, the part of the lens for far vision can also blur the image of the near object.
Although alternating vision lenses have been proposed, the vision provided with such lenses can be less than ideal in at least some instances. Alternating vision can be provided by designs in which the optical zones are separated from each other. The optical center of each zone comes in alignment with the pupillary center as the lens is translated upwards during downward gaze and translated downward during upward gaze. However, it can be difficult for a user to translate such lenses and user satisfaction and control with this sliding approach can be less than ideal.
Although accommodating contact lenses with fluidic coupling have been proposed, the results with such lenses can be less than ideal. The prior accommodating fluidic contact lenses can have less than ideal optical surfaces, as the shapes of the prior accommodating contact lenses for near vision can be less than ideal in at least some instances. Work in relation to embodiments suggest that inflation of the central portion of the prior art fluidic accommodating lenses caused by an increase in hydraulic pressure may lead to optical distortions of the anterior surface. Work in relation to embodiments also suggests that the range of optical correction of the prior accommodating fluidic contact lenses can be less than ideal in at least some instances.
In light of the above, it would be desirable to provide improved accommodating contact lenses. Ideally such lenses would be easy for the user to adjust the focus, provide crisp images with sharp focus with decreased optical artifacts, be comfortable, provide extended wear, and be readily manufactured. The embodiments disclosed herein overcome at least some of the deficiencies of the prior lenses.